Experiments with scale models of oil collectors for subsea well blowouts     

James J. Burgess  Jerome H. Milgram 《Applied Ocean Research》1983,5(1):2-12

Laboratory experiments on conically shaped oil collectors beneath a marine riser are described. The collection concept involves oil, water and gas entering the collector and being driven into a separating sytem by gas-lift. A parametric study involving various collector shapes, heights above the wellhead, and gas, oil and water flow rates was carried out. The important dimensionless variables were identified and quantified with the conclusion that effective collection is possible if the collector height is sufficiently small and the ratio of water pumped to gas flow is sufficiently large. Increased collector heights can be accommodated at the expense of requiring increased water flows by use of larger diameter risers. The amount of gas required for most efficient oil collection is found to be much less than is expected to come from most blowouts when a single collector and riser system is used. This difficulty can be greatly diminished by the use of a specially designed gas-separating collector which passes most of the gas to the surface through a riser separate from the one which carries the liquids.  相似文献   

Measurements of the surface flow above round bubble plumes     

Jerome H. Milgram  James J. Burgess 《Applied Ocean Research》1984,6(1):40-44

When a bubble plume exists beneath a free surface, such as after a subsea gas well blowout, a generally horizontal flow occurs in the vicinity of the surface and this flow is influenced by the fact that the surface is free. Two very different theories for such surface flows have been developed in the past and the bases of these theories are reviewed here. The results of measurements of surface flows above plumes of relatively large scale are given. These are compared with both of the existing theories. One theory is found to be accurate at small radii from the plume centre and the other theory is found to be accurate at large radii. The needed boundary condition for the theory that is accurate at large radii is supplied by the results of the theory that is accurate at small radii.  相似文献   

Hydrological Evaluation of the Canadian Meteorological Ensemble Reforecast Product     

Mabrouk Abaza  François Anctil  Vincent Fortin  Luc Perreault 《大气与海洋》2017,55(3):195-211

This paper evaluates the quality of the ensemble hydrological reforecasts obtained using the 18-year ensemble meteorological reforecast dataset available from the Canadian Centre for Meteorological and Environmental Prediction (CCMEP). This study focuses on four large watersheds in the province of Quebec. A distribution-based scaling (DBS) post-processing method is used to correct the 18-year ensemble precipitation reforecasts. An Ensemble Kalman Filter (EnKF) assimilation technique is also assessed to improve the initial conditions of the hydrologic model. There is a slight improvement in performance and reliability after applying the DBS approach to precipitation reforecasts, but this technique induces a reduction in the spread. The impact of the integration of the post-processed precipitation into the hydrologic model is also quite marginal. However, the addition of an EnKF provides better ensemble hydrological reforecasts with high performance, reliability, and skill, especially in the first reforecast horizons. The best results are, however, generally obtained when using DBS and an EnKF together. Combining DBS and an EnKF, hydrological forecasts for the next two weeks are obtained using the CCMEP reforecast and also the second generation Global Ensemble Forecast System (GEFS v2) reforecast, which is considered a reference. Forecasts of comparable skill and spread are obtained, with CCMEP-based forecasts showing better spread during the first week, and GEFS v2–based reforecasts showing better skill and spread during the second week. Finally, it is shown that the two meteorological reforecast products assessed in this study have similar economic value for hydrological forecasting applications based on the cost–loss model.  相似文献   

Soil evolution and subalpine ecosystem changes in the French Alps inferred from geochemical analysis of lacustrine sediments   总被引：1，自引：0，他引：1  

Brice Mourier  Jerome Poulenard  Christopher Carcaillet  David Williamson 《Journal of Paleolimnology》2010,44(2):571-587

This study aimed to reconstruct the history of soil development, ecosystem changes and associated erosional processes in a small mountain lacustrine basin at the decennial to millennial scale. Geochemical proxies of soil evolution were analysed in the Holocene lacustrine sediments and peats from Thyl Lake, Maurienne Valley, French Alps. Podzolization and chemical weathering processes were assessed using secondary Al- and Fe-bearing phases together with major and Rare Earth Elements (REE). The resulting proxy records, spanning ca. 4,400 years between 8.6 and 4.2 cal ka BP, indicate that progressive pedogenesis occurred after deglaciation in a relatively stable subalpine ecosystem. As shown by the associated increase in Al- and Fe-bearing phases and some REE fractions, the establishment of a mixed cembra pine ecosystem from ca. 7.2–6.5 ka BP was associated with enhanced podzolisation processes in the catchment. The progressive soil development was followed by a rapid transformation of the local environment and plant cover (the open waters of the lake were replaced by a confined peat environment) together with changes in forest fire regimes from ca. 6.8 ka BP. Depleted REE patterns, associated with low contents of secondary Al and Fe, suggest a decrease in chemical weathering and podzolization in the catchment at that time, possibly associated with local intensification of weathering and drainage processes in a relatively acidic peat environment. The higher variability of cembra pine and the increased abundance of sedge and other herbaceous plant remains in the lake sediment indicate semi-open vegetation environments from 5.7 cal ka BP onwards. Whereas fire events and plant cover appear to be significantly related, the soil processes seem primarily linked to vegetation composition, and secondarily to changes in fire regime.  相似文献   

Review: Carbonate aquifers and future perspectives of karst hydrogeology in India   总被引：2，自引：0，他引：2  

Farooq Ahmad Dar  Jerome Perrin  Shakeel Ahmed  Allu China Narayana 《Hydrogeology Journal》2014,22(7):1493-1506

About 3 % of India’s total land surface is occupied by carbonate rocks which are mostly karstified and constitute a significant source of groundwater. The groundwater drawn from these aquifers matches the water demand of ~35 million people living in 106 districts of the country and also the water needs of livestock, irrigation and industry. The studies on karst in India carried out so far have mostly addressed geology, hydrology and groundwater contamination. A literature survey suggests that there is a need for detailed research, applying new approaches and techniques for proper carbonate aquifer identification, characterization and management. Such specific approaches will improve modeling, exploitation and protection of karst groundwater. An overview of the research carried out on groundwater resources of karst formations in India is presented, which also throws light on the protection of karst aquifers from existing anthropogenic activities such as mining and groundwater over-exploitation.  相似文献   

The effects of geological heterogeneities and piezometric fluctuations on groundwater flow and chemistry in a hard-rock aquifer, southern India   总被引：1，自引：0，他引：1  

Jerome Perrin  Shakeel Ahmed  Daniel Hunkeler 《Hydrogeology Journal》2011,19(6):1189-1201

Crystalline aquifers of semi-arid southern India represent a vital water resource for farming communities. A field study is described that characterizes the hydrodynamic functioning of intensively exploited crystalline aquifers at local scale based on detailed well monitoring during one hydrological year. The main results show large water-table fluctuations caused by monsoon recharge and pumping, high spatial variability in well discharges, and a decrease of well yields as the water table decreases. Groundwater chemistry is also spatially variable with the existence of aquifer compartments within which mixing occurs. The observed variability and compartmentalization is explained by geological heterogeneities which play a major role in controlling groundwater flow and connectivity in the aquifer. The position of the water table within the fracture network will determine the degree of connectivity between aquifer compartments and well discharge. The presented aquifer conceptual model suggests several consequences: (1) over-exploitation leads to a drop in well discharge, (2) intensive pumping may contribute to the hydraulic containment of contaminants, (3) groundwater quality is highly variable even at local scale, (4) geological discontinuities may be used to assist in the location of drinking-supply wells, (5) modeling should integrate threshold effects due to water-table fluctuations.  相似文献   

Aquaterra Incognita: Lost Land Beneath The Sea     

Jerome E. Dobson 《Geographical review》2014,104(2):123-138

The author proposes scientific recognition of an existing, previously undefined and unnamed global feature. Aquaterra is suggested as the new name for the lands that were alternately exposed and inundated as ice sheets advanced and retreated over the past 120,000 years. The vertical amplitude of sea level change amounts to 130 meters, and the aggregate global area of aquaterra equates to the continent of North America. The time period coincides with the total span during which modern humans are known to have existed.  相似文献   

Causes of Climate. John G. Lockwood; The Atmosphere. Frederick K. Lutgens and Edward J. Tarbuck; Land in America. Richard N. L. Andrews,Editor     

Jay Harman  Jerome M. Clemens  Paul F. Mattingly 《自然地理学》2013,34(2):197-200

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Lattice Boltzmann simulation of turbulence-induced flocculation of cohesive sediment   总被引：1，自引：0，他引：1  

Jin-Feng Zhang  Qing-He Zhang  Jerome P.-Y. Maa  Guang-Quan Qiao 《Ocean Dynamics》2013,63(9-10):1123-1135

Both the floc formation and floc breakup of cohesive sediment are affected by turbulent shear which is recognized as one of the most important parameters, and thus, on the settling and transport of cohesive sediment. In this study, the development of floc characteristics at early stage and steady-state of flocculation were investigated via a three-dimensional lattice Boltzmann numerical model for turbulence-induced flocculation. Simulations for collision and aggregation of various size particles, floc growth, and breakup in isotropic and homogenous turbulent flows with different shear stresses were conducted. Model results for the temporal evolution of floc size distribution show that the normalized floc size distributions is time-independent during early stage of flocculation, and at steady-state, shear rate has no effect on the shape of normalized floc size distribution. Furthermore, the size, settling velocity, and effective density of flocs at the non-equilibrium flocculation stage do not change significantly for shear stresses in the range 0–0.4 N m^?2. The relationships between floc size and settling velocity established during floc growth stages and that during steady-states are different.  相似文献   

Erratum to: A two-dimensional probabilistic acute human-health risk assessment of insecticide exposure after adult mosquito management     

Jerome J. Schleier III  Paula A. Macedo  Ryan S. Davis  Leslie M. Shama  Robert K. D. Peterson 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(8):1163-1164

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